From patchwork Tue Apr 26 08:21:52 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 566503 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 81349C4332F for ; Tue, 26 Apr 2022 09:07:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1346687AbiDZJIx (ORCPT ); Tue, 26 Apr 2022 05:08:53 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38556 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1345975AbiDZJG3 (ORCPT ); Tue, 26 Apr 2022 05:06:29 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B3F0013C285; Tue, 26 Apr 2022 01:47:52 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 6D88AB81A2F; Tue, 26 Apr 2022 08:47:51 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id ADDA3C385A4; Tue, 26 Apr 2022 08:47:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1650962870; bh=wa6DKY7ihCAiI4ORJ4Lemo2W/kJEgxqyoapglfQxiiI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=fvr2dVtONJ4d3hKOoE34bkvBT2yLepHnQE4/dOVE0tgiSs9DLRO8BpGGj6UOpvevn 1efBlLdpTpkukBmhLtSJOmxnhaENb8scq+hf4GgEVrWHVIlvTpVrcR/w0k/pLqOp79 tbDj77BbEys31oK0vLFnB4iVlBXK24LYzSWydXlI= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Guo Ren , Guo Ren , Max Filippov , Masami Hiramatsu Subject: [PATCH 5.17 117/146] xtensa: patch_text: Fixup last cpu should be master Date: Tue, 26 Apr 2022 10:21:52 +0200 Message-Id: <20220426081753.345440056@linuxfoundation.org> X-Mailer: git-send-email 2.36.0 In-Reply-To: <20220426081750.051179617@linuxfoundation.org> References: <20220426081750.051179617@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Guo Ren commit ee69d4be8fd064cd08270b4808d2dfece3614ee0 upstream. These patch_text implementations are using stop_machine_cpuslocked infrastructure with atomic cpu_count. The original idea: When the master CPU patch_text, the others should wait for it. But current implementation is using the first CPU as master, which couldn't guarantee the remaining CPUs are waiting. This patch changes the last CPU as the master to solve the potential risk. Fixes: 64711f9a47d4 ("xtensa: implement jump_label support") Signed-off-by: Guo Ren Signed-off-by: Guo Ren Reviewed-by: Max Filippov Reviewed-by: Masami Hiramatsu Cc: Message-Id: <20220407073323.743224-4-guoren@kernel.org> Signed-off-by: Max Filippov Signed-off-by: Greg Kroah-Hartman --- arch/xtensa/kernel/jump_label.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/arch/xtensa/kernel/jump_label.c +++ b/arch/xtensa/kernel/jump_label.c @@ -40,7 +40,7 @@ static int patch_text_stop_machine(void { struct patch *patch = data; - if (atomic_inc_return(&patch->cpu_count) == 1) { + if (atomic_inc_return(&patch->cpu_count) == num_online_cpus()) { local_patch_text(patch->addr, patch->data, patch->sz); atomic_inc(&patch->cpu_count); } else {